The overall objective of this project is to analyze the formation of specific nerve connections between retinal ganglion cells and the optic tectum in lower vertebrates. It utilizes the technique of transplanting the eye primordium form one orbit to another in Xenopus embryos and determining the retinotectal projection maps in young adult toads. This project also evaluates the plasticity in the retinotectal connectivity in adult goldfish, utilizing electrophysiological, anatomical and psychophysical techniques. BIBLIOGRAPHIC REFERENCES: Sharma, S.C., Visual projections in Surgically created "Compound" tectum in adult goldfish. Brain Research. 93: 49-501, 1975. Yager, D. and Sharma, S.C., Evidence for visual function mediated by anomalous projection in goldfish. Nature (London). 256: 5517, 1975.